Apparatus for grinding gun barrels and cylindrical surfaces



July 4, 1933.

M. C. HUTTO APPARATUS FOR GRINDING GUN BARRELS AND CYLINDRICAL SURFACES Filed July 22, 1930 6 Sheets-Sheet 1 M. C. HUTTO July 4, 1933.

6 Sheets-Sheet 2 APPARATUS FOR GRINDING GUN BARRELS AND CYLINDRICAL SURFACES Filed July 22, 1930 Q mm QN July 4, 1933. M. c. HUTTO 1,916,267

APPARATUS FOR GRINDING GUN BARRELS AND CYLINDRICAL SURFACES Filed July 22, 1950 e Sheets-Sheet a llll I nuanfoz villi; Illl MN $8 MRS July 4, 1933.

v M. c. HUTTO M. C. HUTTO July 4, 1933.

APPARATUS FOR GRINDING GUN BARRELS AND CYLINDRICAL SURFACES Filed July 22, 1930 6 Sheets-Sheet 6 gwuemtoz a s G c:

S c: S

= C: a S S s .mwm 'llllllllll llll Patented July 4, 1933 uru'rso stares craters MARSDEN C. HUTTO, OF DETROIT, MICHIGAIF, AFSIGNGR TO HU'TTO) EEGINEEEINQ 60E- IANY, ENG, 033 DETROIT, MICHIGAN, A @OFJEOFATEQN 9E MIGEIGAN APPARATUS FOR GRINDINQ- GUN BARRELS A2333 CYLIBIDRICAL FJURFAGEF Application filed July 22, 1930. serial No. 469,502.

This invention relates to an apparatus for grinding cylindrical surfaces such as the barrels of large diameter guns, cannons or heavy ordnance,

large caliber or bore may be reground or reconditioned without requiring the same to be dismounted or removed from their mountings which normally support them when installed W for use.

When guns or cannons of large caliber have become worn due to repeated firing of the same it becomes necessary to rebore them in order to restore their accuracy. To do this it has been necessary to dismount the guns, transport the same to andfrom the machme shop where the regrinding was performed and then remount the guns. This not only involves a great deal of labor and expense but also is attended with a loss of time and long interruption in the use of the guns which is of great importancein the case of guns mounted onv war ships and in fortifications inasmuch as the ships cannot be used most effectively when one or more of their guns are removed for purposes of reboring and a fortification is also handicapped when part of its equipment is temporarily removed.

One of the objects of thisinvention is to 39 provide a grinding apparatus for boring or reconditioning the barrels of heavy ordnance which enables the grinding of the bores of such barrels to be accomplished eficiently, ex-

peditiously and economically.

A further object of this invention is to enable the boring of such a barrel to be effected 4 without removing the barrel from its mount-- ing, thereby reducing to a minimum interruption in the use of the gun and the equipment associated therewith.

In the accompanying drawings: Figure 1 is a fragmentary perspective view, partly in section, of my grinding apparatus applied to the front portion or muzzle of a large caliber gun barrel.

Figure 2 is a similar view of the mid-section of a gun barrel and a part of the grind ing apparatus therein.

Figure 3 is a similar view of the rear part 7 and more particularly to an 5 apparatus of this character-whereby guns of or breech section of a gun barrel and a part of the grinding apparatus therein.

Flgure i is a vertical longitudinal section, on an enlarged scale, of the muzzle portion of the gun barrel and part of the grinding apparatus mounted thereon, the section bemg taken on line Fig. 6.

Figure 5 is a fragmentary side elevation,

partly in section, of the mechanism for driv-- mg the working parts of this grinding ap-' paratus.

Figure 6 is a cross section taken on line 66, Fig. 4.

Figure 7 is a cross section taken on line 7-7, Fig. 5.

Figure 8 is .a fragmentary vertical section, on an enlarged scale, of the means fer connecting the tool'with the driving shaft and the mechanism for adjusting the diameter of the tool. w

Figure 9 is a vertical transverse section taken on line 99, Fig. 4.

Figure 10 is a vertical transverse section taken on line 10- -10', Fig. 8.-

Figure 11 is a vertical transverse section, on an enlarged scale, taken on line 1111, Fig. 5. p

v Figure 12 is a perspective view of the key forming part of the mechanism for longitudinally reciprocating the grinding tool in the bore of the gun barrel.

Figure 13 is a fragmentary longitudinal section, on an enlarged. scale, showing the mechanism for connecting the grinding tool with its driving shaft and the means for adjusting the diameter of the tool, and the means for guiding the driving shaft and as" sociated parts in the gun barrel.

Figure 14 is a cross section taken on line 1414, Fig. 5.

Figure 15 is a fragmentary side view of the means for coupling the main driving shaft at its front end With the body or the grinding tool.

Figure 16 is a side view of the adjusting collar forming part of the means for adjusting the working diameter of the tool.

Figures 1'? and 18 are end views of the co-operating coupling plugs for-connecting opposing ends of two sections of the adjusting shaft.

Figure 19 is a diagrammatic wiring diagram of the electrical connections of the grinding apparatus.

In the following description similar characters of reference indicate like parts in the several figures of the drawings.

Although this grinding apparatus is adapted to grind the bores of ordnance of various constructions and mounted aboard ship or on fortifications, the same is concerned wholly with the barrel of such ordnance which in the present example consists of a forwardly tapering body 10 having a straight longitudinal cylindrical bore 20, a rearwardly tapering or conical external bead or collar 21 arranged on the muzzle or front end of the barrel and a breech 22 arranged at the rear end of the body and having an ammunition loading chamber 23 communicating with the bore of the gun barrel.

In its general organization this grinding apparatus comprises a tool which is adapted to rotate and reciprocate lengthwise in the bore of the gun barrel and provided with abrasive members orbits which engage with said bore for grinding and polishing the same, means for effecting such rotation and reciprocation of the tool from the exterior of the gun barrel, means for adjusting the working diameter of the tool, and means for detachably mounting the apparatus on the muzzle of the gun barrel and maintaining the same in the proper relation during the operation of grinding the bore of the same.

The tool for grinding the bore of the gun barrel may be variously organized but the construction shown in the drawings is preferred as it has worked satisfactorily in actual use and as there shown the same is constructed as follows:

The body of the tool comprises a central longitudinal hub 24 having preferably the form of an outer tube, and front and rear heads 25, 26 mounted 011 the front and rear ends of the body tube and having preferably the form of disks. The central hub and heads of the tool body are preferably held together by means of an outer spacing tube or sleeve 27 surrounding the hub and bearing at itsopposite ends against the opposing sides of the disk shaped heads, a coupling sleeve or driven head 28 riveted or otherwise secured to the rear end of the hub 24 and engaging the outer side of the rear head 26, and clamping screw nuts 29 working on the externally screw threaded front end of the hub and engaging with the outer side of the front head 25. A rigid connection between the main body members is thus obtained so that as a whole the tool body is strong and light.

Around the periphery of the body heads 1s arranged an annular row of longitudinal supporting bars 30 which are capable of radial movement on the tool body by mounting each supporting bar at its opposite ends on guide rods 31 which are slidable radially on the respective body heads. The connection between each guide rod and the respective supporting bar is preferably effected by providing the outer end of the rod 31 with an enlarged head 32 which is arranged in an opening 33 in the adjacent part of the supporting bar and a pin 34 passing transversely through the head 32 and the adjacent part of the supporting bar. By this means a pivotal connection is obtained between the supporting bar and its guide rods which permits these members to turn slightly relativcly to each other and prevents binding of the rods in their guideways in the body in case the rods at opposite ends of the body do not slide radially in unison. Each of the guide rods 31 slides at its outer end in guide bushings 36 secured in the inner and outer parts of a radial opening 331 in the respective body head which bushings are made of hardened material as compared with the body heads 25, 26 and are accurately fitted to said rod, thereby insuring proper guiding of the rods on the body heads and long wear of the cooperating surfaces in the rods and bushings.

On the outer side of each supporting bar adjacent to opposite ends thereof are mounted abrasive members or stones 38 which are adapted to engage the bore of the gun barrel and grind and polish the same and which preferably have the form of longitudinal sticks and each is mounted on a holder 39 provided on its inner side with retaining pins 40 engaging with openings 41 formed in the respective supporting bar on opposite sides of the adjacent guide rod 31 and said stone holder being spaced the proper distance from the outer side of the supporting bar by washers 42 surrounding the retaining pins 40 between said holders and the supporting bar, as shown in Figs. 4 and 9.

The several supporting bars are yieldingly drawn inwardly for contracting the working diameter of the tool by annular springs 43 engaging with seats 44 at opposite ends of the supporting bars, as shown in Figs. 4 and 9.

The inner ends of the sets of guide rods 31 project through openings 45 in the side of the body hub and beyond the bore thereof and into engagement with oppositely pointing or working cones, cams or wedge members 46, 47 which are slidable lengthwise in the front and rear parts of the body hub and form part of the means for adjusting the Working diameter of the tool. The two cones are adjustably connected by an adj usting screw the body 48 of which passes lengthwise through axial openings in the cones and the front end of which is provided with a left hand screw thread 49 working in a thread in he central opening of the front cone and proand the working diameter of the stones thereon to'be expanded, while upon turning the adjusting screw 48 in the opposite direction, the cones will be separated by the inward pressure of the springs 43 exerted against the same through the medium of the guide rods 31. The rear cone 47 is preferably free to slide and also turn in the bore of the tool body but the frontcone 46 is free to slide lengthwise in the bore of the tool body but compelled to turn therewith by a key or pin 51 arranged on the hub ofthe body and engaging with the longitudinal I barrel and the frame of the grinding appakeyway 52 on the side of the cone 46, as shown in Fig. 4.

The mechanism for rotating and reciproeating the tool in the bore of the gun barrel and also the means externally of the gun barrel for adjusting the working diameter of the tool are mounted on a frame which is temporarily secured to the gun barrel and in order to maintain the grinding mecha nism in proper axial alinement with the gun barrel. This framemay be variously constructed but as shown in Figs. 1, 4, 5, 6 and 7, the same comprises a front cross head 53 which is detachably secured to the muzzle of the gun barrel, a rear cross head,54 and two lower longitudinal rods 55 connecting the lower parts of said front and rear cross heads. rear cross heads are additionally connected by upper longitudinal metal plates 56 and lower longitudinal runners or shoes 57 of wood which serve as skids whereby the apparatus can he slid easily from one place to another during transportation.

The means for detachably connecting the supporting frame of the grinding apparatus include a clamping sleeve which is divided diametrically to form two like half sections, each section having a semi-cylindrical peripheral wall 58 adapted to surround one half of the muzzle of the gun barrel and a bearing flange 59 projecting radially inwardly from the outer end of the respective wall and-adapted to bear against the transverse face on the end of the muzzle of the gun barrel and also connected with the front cross head of the supporting frame by bolt-s 60. On their inner sides the semi-cylindrical walls of the clamping sleeve are provided with jaws 61 which grip the periphery of the conical head or collar and secure the frame thereto in a position in which the parts The lower sides of the front and of the grinder are properly alined or centered relatively to the bore of the gun barrel. The jaws of the clamping sleeve are thus drawn tightly against the collar of the nozzle by clamping bolts 62 connecting lugs 63' on the opposing ends of the clamping sleeve sections, as shown in Figs. 1 and 6,

By these clamping means the grinding apparatus may bereadily attached to and removed from gun barrels of the same size, and by employing semi-cylindrical clamp-- ing sleeve sections of different sizes and grinding tools of corresponding sizes appropriate for given sizes of guns the same tool actuating and diameter adjusting mechanism may be used for grinding guns of different sizes or bores.

The mechanism for rotating and reciprocating the tool for grinding the bore of a gun barrel as shown in the drawings is constructed as follows:

T he numeral 64 represents a carriage reclprocable lengthwise of the axis of the gun ratus and guided in this movement by means of guide eyes 65 formed on opposite sides of the lower part of thecarriage and slidable lengthwise on the lower longitudinal rods 55 of the main frame. and also provided on its upper part with a pair of thrust guide eyes 66 arranged lengthwise in line but spaced apart and receiving a longitudinal horizontal shaft 67 which also serves as a guide rod for the carriage. This shaft is journaled at its rear end in a bearing 68 on the rear cross head 54 of the main frame while its front end is journaled in a bearing 69 on the front cross head 53 of this frame, but this shaft is held against longitudinal movement by means of front and rear shoulders 70, 7 L thereon engaging the opposing ends'of the front and rear bearings 69, 68, as shown in Figs. 1, 4 and 5. Nearly all thatpart of the shaft 67 between its front and rear bearings is provided with a screw thread 72. Between the threaded part of the shaft 67 works in an internally threaded screw sleeve which is composed of two semi-cylindrical sections 73, 73 which are detachably connected with each otherby screws 74 connecting the corresponding longitudinal edges of the. screw sleeve. The opposite ends of the latter engage with the opposing ends of'the upper guide eyes 66 and this screw eye is coupled with the capriage by means of a key 75 arranged in a longitudinal seat 76formed between the lower opposing longitudinal edges of the split screw sleeve and engaging its ends with the guide eyes 65, and provided on its under side with a depending coupling pin 77 engaging with an opening 78 in the upper part of the carriage, as shown in Figs. 5, 11 and 12.

Upon turning the screw shaft 67 in one direction, the carriage and the parts mounted thereon are moved in one direction lengthwise of the main frame and gun barrel and upon turning the screw shaft in the opposite direction the direction of the longitudinal movement of the carriage and the parts mounted thereon is reversed; this reciprocating motion being due to the screw sleeve running on the main shaft as a screw .nut and transmitting this motion to the carriage by means of the connection therebetw een.

The rotation of the screw shaft 67 is. produced by a motor 79, preferably of the electrically operated type, which is mounted on a platform or bracket 80 on the rear side of the rear main frame cross head and having its shaft 81 provided with a small gearpinion 82 which meshes with a large internal gear wheel 83 secured to the rear end of the screw shaft, as shown in Fig. 5. This electric motor is so constructed that the same can be reversed and thus permit of turning the screw shaft in opposite directions for reciprocating the carriage.

A controlling mechanism is provided for controlling the operations of the carriage reciprocating motor 79 which mechanism is so organized that this motor may be started and stopped at will, the length of the strokes or reciprocations of the carriage may be varied to suit the length of the cylindrical surface which is being ground, and the movement of the carriage is also automatically reversed at the end of each stroke so that the carriage reeiprocates as long as desired without requiring any attention of the operator. This controlling mechanism is preferably of an electrical character and combined with the means which control the rotation of the tool, as will later appear. Some parts of this controlling mechanism are enclosed in a housing 189 mounted on the rear part of the main frame of the guiding apparatus, as shown in Fig. 1, so that the apparatus forms a complete portable unit.

Rigidl mounted within the carriage is a longitud nal shell or casing the rear part 89 of which contains an electric motor 90 for rotating the grinding tool and within the front part 91 of this shell is arranged a reducing gear whereby the rotary motion of the motor 901s transmitted at a reduced speed to a longitudinal driving shaft 92 projecting from the front end of the shell section 91, as shown in Fig. 5. To the front end of the tool driving shaft a driving head 93 is secured by transverse pins 94, as shown in Fig. 8, or other suitable means. Motion is transmitted from this driving head 93 to the driven head 28 of the grinding tool body by a sectional motion transmitting shaft which is made in sections of like construction so that a larger or smaller number of such sections may be coupled for obtaining a shaft of the required length which will permit of reaching fully into gun barrels of various lengths. The

several sections of this transmitting shaft are all alike and interchangeable and also combined with means for guiding the same and maintaining them centrally in the gun barrel which is being ground, and the endmost sections of this shaft are connected by universal joint couplings with the driving and driven heads 93 and 28, respectively. For this purpose each section of the transmitting shaft has a longitudinal tubular body 95. The tubular body 95 of the rear-most section of the intermediate transmitting shaft is provided internally at its reanend with a bushing 96 provided with a neck 97 terminating at its rear end in a spherical knuckle 98 which is arranged within asocket 99 at the front end of the driving sleeve 93 and which is provided on dian'ietrieally opposite sides with coupling pins 100 engaging with L-shaped or bayonet slots 101 in the adjacent parts of the driving head 93, as shown in Figs. 8 and 15, thereby permitting this head and the rearmost transmitting shaft section to be readily coupled and uncoupled and also forming a universal joint between the same which permits transmission of motion without any binding or cramping action if the axes of the driving head and transmitting shaft are not in absolute alinement.

The tubular body 95 of the foremost section of the transmitting shaft is provided externally at its front end with a coupling sleeve 102 and in front of the latter is arranged a neck 103 terminating at its front end in a spherical knuckle 104 which is arranged in a socket 105 at the rear end of the driven couplinghead 28 and which is provided on its diametrically opposite sides with coupling pins 106 engaging with L-shaped or bayonet slots 107 in the sides of the driven sleeve or head 28, as shown in Figs. 13 and 10. The sleeve 102 and the neck 103 are provided with external flanges 108, 109, respectively, which are detachably connected and compelled to turn together by'means of screws 110 and dowels 111, as shown in'Figs. 13 and 16, or by other suitable means.

The opposing ends of the tubular bodies 95 of the several transmitting shaft sections are detachably connected by means of cxternal sleeves or collars 112 secured to these ends by riveting brazing or otherwise and providing these collars respectively with annular flanges 115 which are detachably connected and compelled to turn together when coupled by means of screws 114 and dowels 1161. The end of the tubular body 95 of one intermediate shaft section having a collar 112 stops short of the outer face of this collar so as to form a socket 116 therein and the end of the tubular body 95 having the companion collar 112 extends beyond the outer face of the latter so as to form a tenon 117 thereon which fits or-telescopes into the socket 116 of the adjacent collar 112, thereby causing the opposing ends of the shaft bodies to be maintained in alinement with one another when in use and still permit them to be readily assembled and disassembled.

In order to support the intermediate transmitting shaft centrally within the gun barrel and prevent the same from sagging, particularly when the same is very long for grinding gun barrels of great length, means are provided for guiding this shaft at inter-' vals in the bore of the gun barrel. This is preferably accomplished by a plurality of pilot disks or circular guide members 118 each of which engages its periphery with the bore of the gun barrel and is provided with a central circular hub 119 which is seated on the periphery of a pair of opposed flanges on two adjacent shaft bodies 95 andis clamped therein by engagement of rims 113 on said flanges with the opposite sides of said hub forming an annular groove for receiving the latter, as shown in Figs. 1, 2, 3, 4 and 13. Theseguide disks slide and turn in the bore of the gun barrel while the vtool is reciprocated androtated therein during the operation of grinding the bore and maintain the transmitting shaft in its central position within the. bore of the gun barrel so that no cramping or binding will occur and the grinding can be accomplished easily and expeditiously and with a minimum expenditure of power.

The mechanism for shifting the abrasive: members or stones radially on the tool body for adjusting the working diameter of the tool is constructed as follows:

The numeral 121 represents an adjusting sleeve rotatable on the driving head 93 but held against longitudinal movement thereon by a rearwardly facing shoulder 122 on the adjusting sleeve engaging a forwardly facing shoulder 123 on the driving head, and a collar 124 secured to the front part of the driving head engaging with the front end of the adjusting sleeve, as shown in Figs. 8 and 13. This adjusting sleeve may either turn clockwise with the driving head 93 when "the working diameter of the tool is not to be changed or this adjusting sleeve may be held agalnst turning with the driving head when the stone holders are to be moved radiv ally outwardly for taking up stone wear or openings 128 in the brake shoes so as to pre-= vent the latter from rotating with the driving head, a hinge pin 129 pivotally connecting the brake shoes on one side ofthe axis of the driving head 93, and means for tight ening the shoes on said adjusting sleeve or releasing the same comprising a draw rod 130 pivoted by a pin 131 to that end of one shoe opposite the hinge-pin 129 and passing through an eye 132 on the corresponding endof the other brake shoe, a rotary cam 133 provided with a handle, 134 andarranged on the draw rod 130 between a cam 135 on the eye 132 and screw nuts 136 on this draw rod, and a spring 137 surrounding the draw rod between the adjacent ends of said brake shoes. Upon turning the cam handle 134 in one. direction the opposing cams 133, 135, operate to press the brake shoes against opposite sides of the adjusting sleeves and either stop or retard its rotary movement with the driving head, while upon turning the handle 134 in the opposite direction the brake shoes will be spread and released from gripping engagement with the adjusting sleeve by the expansion of the spring 137 whereby this sleeve is again permitted to turn with the driving head 93.

The means for transmitting motion from the adjusting sleeve 121 to the cone adjusting screw 48 includes gearing extending from the periphery to the axis of the driving head and shafting extending from this gearing to the cone adjusting screw 48. This gearing comprises an internal gear ring 138 secured to the inner side of the adjusting sleeve 121 at the front end thereof, a central gear wheel 139 j ournaled axially within the driving sleeve by means of a rearwardly projecting hub 140 on this gear wheel turning in a central bearing 141 in the driving head, an outerintermediate gear pinion 142 pivoted on the driving head 93 and meshing with the internal gear ring 138, and an inner intermediate gear pinion 143 pivoted on the driving head 93 and meshing on its outer side with the outer interme diate gear pinion 142 and meshing on its inner side with the central gear wheel 139, as shown in Fig. 8. The latter is confined in the driving head by a split retaining ring 144 engaging an internal groove 145 in the bore of the driving head in front of the central gear wheel.

In its center the central gear wheel is provided with a square opening 146 which receives a square coupling rod pin or spindle 147 whereby this gear wheel and pin are compelled to turn together but are free to move lengthwise relatively to one another.

The shafting which transmits motion from the central gear wheel 139 to the cone adjusting screw 48 comprises a plurality of adjusting shaft sections corresponding tothe sections of the intermediate driving shaft sections,.each adjusting shaft section having a tubular body 148 which is of substantially the same length as the companion driving ing its front end with a square socket 173 at shaft section and is mounted therein so as to the rear end of the head 50 of the cone adjustbe capable of turning but incapable of moving screw 48, and a universal joint connecting in lengthwise relatively thereto so that in the rear end of the coupling rod 172 and the e ect each outer driving shaft section and the front end of the coupling shaft 17 and comcompanion inner adjusting shaft section toprising a front swivel block 173 connected at 7 gether form a unit of this means for transits front end by a transverse pin 174 with the mittin motion for driving the tool and for rear end of the coupling rod 172 and a rear adjusting the working diameter of the same. swivel block 175 connected by a transverse The rear end of the body,148 of the rearmost pin 176 with the rear end of the front swivel adjusting shaft section isjournaled in abearblock and having trunnions or pins 177 at ing 149 in the neck 97 of the bushing 96 and right angles to the pin 176 for pivotally conis provided with a plug 150 having a fornecting the rear swivel block 175 with the wardly facing annular shoulder 151 engaging front end of the short coupling shaft 170, as

the rear side of the bearing 149 and a rearshown in Figs. 4 and 13. wardly projecting socket 152 in which is By this means rotary movement of the adloosely secured the front end of the coupling justing sleeve 121 relative to the driving head rod 147 by a transverse pin 153 passing and driving shaft sections will be transmitted loosely through the rod 147 and the socket by the sectional adjusting shaft to the means 152 so as to form in effect a swivel joint whereby the working diameter of the stones or universally movable coupling between is adjusted which adjustment can be effected these members. while the apparatus is in operation. By con- The rear end of each of the other adjuststructing the driving shaft and adjusting ing shaft sections 148 is provid d with a 11 shaft in sections of corresponding length each 154 which is secured therein by a transverse f whi h forms a unit capable of being aspin 155 or otherwise and has a reduced neck Sembled with other units it is possibleto vary 156 journaled in a bearing disk 157 e ur d the length of the means for driving the tool' against an internal shoulder 158 in the adjaand adjusting the diameter of the same to cent part of the driving shaft section 95 by uit different length of bores of guns and brazing or otherwise. If desired a washer ther Conditions.

159 may be mounted on the neck 156 and held When the grinding apparatus is in norm l in engagement with the rear side of the bear- '9P 'ati0n the tool driving shaft and the ading disk 157 by a pin 160 passing through the justing shaft arranged in the driving shaft neck 156. The, latter i pr vid d ith a f turn in unison clockwise or toward the right ,wardly projecting coupling tongue 161 which throughout the lengthof both of these shafts is flat sided or of prismatic form in cross secwhereby thflstones remain in the Same radial tion. In the front endof each adjusting shaft P i iOn on the tool body and operate on the section is secured a plug 162 having aforward- $11118 Working diameterwhile the l i I a fi ly projecting reduced neck 163 which turns'in g and reciprocating in the bore of the gun a bearing disk 164 secured against an internal barrel other cylindrical y- Whenever shoulder 165 i th dja t, t f th it is desired to move the grinding stones outspective driving shaft section and engaging ardly forthe purpose of increasing the against a shoulder166 on the respective plug. Working diameter of the Same the 1 as shown i Fi 13 If d i d a washer turns the handle 134 of'the brake shoes 125 267 may be held on the neck 163 and in 50 that the c pe cams 133,135, cause engagement ith th f t id f th the brake shoes to grip the adjusting sleeve spectlve b i di k b a i 1 7 E h f 121 and either stop rotation of the same' or th necks f th f m; plugs f th dj ti retard its rotation relative to the tool drivin shaft sections is provided with a transverse shaft- [When this Occurs the adjusting Sha t groove 168 each ofwhich, except the fored the cone j g" screw 48 against o t 13 d t d t b engaged b th turning or retards rotation of the same relatongue 161 ontherear end of the next reare the 13001 y, whereby the from cone d dj ti h ft ti d th b 46 which turnswith the tool body is screwed couple the several adjusting shaft sections so further ardly 0n the left hand thread 4 that the same in effect form one continuous 0f h bolt 48 S that the two Cones 4 47 shaft. are drawn together and exert a wedge action -The foremost adjusting shaft section is con- 011 the g i e r 31 and force them radially nected with the rear end of the cone adjusting outwardly together with the stone carriers screw by a short coupling shaft 170 journaled or holders mounted thereon, thereby increasaxially 1n bearings 171 in the front driven ing the working diameter of the tool or takhead 103 and provided at its rear end with a ing up wear onthe face of the stones. Upon flat coupling tongue 169 adapted to engage releasing the grip of the brake shoes on the with the front groove 168 of the foremost adjusting sleeve 121 the radially outward ad ustmg shaft section, a longitudinal 'couadj usting action on the stone carriers or holdplmg rod 172 of square cross section engagers ceases. This operation is repeated whention or opposite to the rotation of the tool body which movement of the latter is permitted due to the operation of the gear wheels 139, 142, 143 interposed between the relatively anchored gear ring 138 of the adjusting sleeve 121 and the adjusting shaft which gearing operates to turn the latter anti-clockwise at the same rate as the driving shaft turns clockwise and thus holds the adjustin screw bolt 48 stationary relatively to the too body. When the grinding stones are not being adjusted radially on the tool body the gearing interposed between the adjusting sleeve and the adjusting shaft is idle and turns bodily with the driving shaft and associated parts.

If at any time the grinding stones get stuck in the gun barrel or cylinder due to being set up too tight or other reason and the clockwise rotation of the driving shaft is continued under the action of the power applied to the rear end of the same, then this driving shaft will be subjected to a torque or twisting action during which its rear end will turn clockwise while its front end and the tool mounted thereonv will be Stationar Whenever this occurs the adjusting sha t, which is locked at this time by the gearing 138, 139, 142, 143 at its rear end to the rear end of the driving shaft, is caused to turn clockwise throughout its length with the clockwise moving rear end of the driving shaft. This causes the adjusting bolt 48 which is coupled with the adjusting shaft to also turn clockwise, and as the adjusting bolt has a left hand screw thread 49 working in the internal thread of the front cone 46 the latter is unscrewed from the bolt 48., As a result of this the two cones 46, 47 are separated and present lower parts of their cam surfaces to the guide rods 31, whereby the outward pressure of the stones againstithe cylindrical surfaces of the gun barrel is relieved and the stones are permitted to release their grip on the bore of the gun. The instant this occurs the tool body is. free to resume its clockwise rotation together with the driving shaft which gradually untwists itself and also causes the screw threaded front cone 46 to again screw onto the bolt 48 so that the cones 46; 47 are moved toward each other and present their higher parts to the guide rods 31, whereby the stones are again moved radially outwardly against the bore of the gun barrel. This automatic release of the stones from the bore of the gun barrel occurs as often as the stones get stuck in the barrel and the same are restored to their working position after each release, therebv preventing breaking of the driving and adjusting shafts and other parts of the apparatus which otherwise would be liable to 1 occur if the power were not shut off in time.

Stop means are provided'for limiting the expansion of the stones when the same have reached a predetermined working diameter which means are adjustable for varying this diameter. These stop means are preferably constructed asfollows:

The numeral 178crepresents a stop collar which is mounted on the adjusting sleeve 121 so as to be capable of circumferential adjustment thereon which is preferably accomplished by means of an internal adjusting pin 1-79 on the stop collar adapted to engage with one or another of'an annular row of notches 180 on the periphery of the-adjusting sleeve 121. At the front ends of the adjusting sleeve and stop collar a dial rim 181 is rigidly mounted on the rear driving head of the driving shaft which rim is preferably formed on the collar 124 and provided on its periphery with an annular row of graduations 182 and a stop 183. On the adjacent front edge of the stop collar is arranged a stop 184 which "is adapted to traverse the scale or graduations 182 andalso engage the dial stop 183. In using this stop device the stop collar is moved longitudinally rearward so as to disengage its adjusting pin 17 9 out of engagerotation of the stop collaron the adjusting a sleeve.

Upon now operating the apparatus the stop collar will be held against rotation together with the adjusting sleeve by means of the brake mechanism from time to time whenever radially outward adjustment of the stones is desired. During each of such stopping actions of the adjusting sleeve the stop 183 on the dial ring approaches closer to the stopon i the stop collar due to the rotation of the rear driving head 94 in a clockwise direction whereby the gearing 138, 139, 142., 143 is caused to. turn the adjusting shaft anti,- clockwise and move the stones radially outward through the medium of the cones 46., 47. This radially outward adjustment action of the stones continues until the stop 183 of the dial ring engages the stops 184 of the stop collar at which time the stones can be moved outwardly no further and the grinding of Ilse the bore of the cylinder has reached the desired diameter.

When applying this grinding apparatus to a gun barrel the frame of the apparatus is suitably supported so that the weight of the apparatus is not liable to distort the grinding tool and the parts associated therewith out of alinemcnt with the gun barrel.

Although various means may be employed for starting and stopping the motor 79 and also reversing the motion thereof for operating the tool reciprocating carriage, and also for starting and stopping the tool rotating motor 90, the electrical controlling mechanism shown in the diagram Fig. 19 is suitable and as thus shown the same is organized and operates as follows:

The numerals 190, 191 represent the two feed wires which are connected with an electric current source which is supplied in any desired manner. These feed wires are adapted to be connected with and disconnected from two main delivery wires 192, 193 by a hand switch 194. From the main delivery wires two branch wires 195, 190 lead to the winding of the tool rotating motor 90 one of these last mentioned wires also including a resistance 197 and a switch 198 whereby the circuit through this motor may be opened or closed and also more or less resistance included in the circuit ofthe same in accordance with the speed of rotation desired.

The field or winding of the electric motor 79 for reciprocating the grinding tool lengthwise is connected with two wires 199, 200 which are adapted to be connected with and disconnected from two branch wires 201, 202 of the delivery wires 192', 193 by a reversing switch having two central contacts 203, 204 connected respectively with the wires 201, 202, two pairs of side contacts 205, 206 and 207, 208 arranged on opposite sides of the central contacts 203, 204 and two pairs of reversing contacts 209, 210, and 211, 212 adapted to connect the central contacts 203, 204 either with the side contacts 205. 206 or with the side contacts 207, 208 and thereby cause the electric current to travel through the motor 79 in one direction or the other and thus turn the same accordingly.

The contacts 209, 210 are mounted on a shifting rod 213 which is connected with the armature 214 of a solenoid magnet the coil 215 of which is connected by wires 210, 217, 218 with the wires 201, 202 and with a. rear tappet switch the contacts 219, 220 of which are adapted to be momentarily engaged by a plunger 221 which is shifted liv a rear tappet 222 on the carriage 64.

The contacts 211, 212 are mounted on-a shifting rod 223 which is connected with the armature 224 of a solenoid magnet the coil 225 of which is connected by wires 217, 218, 226, 227 and 228 with the wires 201, 202 and with a front tappet switch the contacts 229,

230 of which are adapted to be momentarily engaged by a plunger 231 which is shifted by a front tappet 232 on the carriage.

The two shifting rods are connected by a rock lever 233 so that these rods are moved in opposite directions and cause the movable switch contacts 209, 210 and 211, 212 to open and close the circuit through the motor 79 alternately in opposite directions. The circuit of the motor 79 also preferably contains a hand switch, as for example the switch 234 in the wires 199, 200. I

In operating this grinding apparatus the required number of driving shaft sections and adjusting shaft sections are assembled and connected with the motor 91 and the switch 234 controlling the tool reciprocating motor 79 are also closed. Assuming that the reversing switch associated with the reversible motor 79 is now in the position shown in Fig. 19 the carriage at this time will be moved longitudinally forward due to the circuit of the motor 79 being closed across contacts 203, 205, 209 and 204, 206, 210, and this circuit being open across contacts 203, 207, 211 and 204, 208, 212. When the carriage nears the limit of its intended forward stroke the tappet 232 pushes the plunger 231 and engages the contacts 229, 230 whereby the coil 225 is energized and caused to move the contacts 211, 212 into engagement with the contacts 203, 207 and 204, 208 and the contacts 209, 210 out of engagement with the contacts 203, 205 and 204, 206, whereby flow of the electric current through the motor 79 is reversed and the carriage together with the tool and other parts mounted thereon are moved backwardly relatively to the gunbarrel. When the carriage nears the limit with are moved longitudinally forward relative to the gun barrel. The tool by this means is reciprocated continuously within the gun barrel while the switches 194 and 234 are closed. The length of the strokes may be adjusted to suit the length of the cycan set up the stones toward the cylindrical surface which is being ground and increase the working diameter of the toolin order to compensate for wear on the stones and removal of stock from the work piece by manipulating the stone adjusting mechanism in the manner described while the grinding appae ratus is in operation. When the grinding has been completed the current is shut off from the motors and the apparatus removed from the gun barrel. 1

By means of this apparatus it is possible a to recondition the bore of a gun barrel after the same has been fired a suficient number of times to become pitted, scored or roughened in its bore, and remove such imperfections without dismounting the gun, thereby permitting of maintaining the gun in the highest state of efficiency with practically no interruption in its availability for constant use, which is an important item in warfare when accuracy of aim and continuous firing of the gun are necessary.

I claim as my invention:

1. A tool-for grinding a cylindrical surface comprising a body having an inner longitudinal tube, disks mounted on o posite ends of said inner tube, an outer tu e surrounding said inner tubeand bearing at its opposite ends against the opposing inner."

sides of said disks, a head arranged at one end of said inner tube and engaging with the outer side of one of said disks, and a screw nut arranged on the opposite end of said inner tube andengaging with the outer side of the other disk; a plurality'of stone holders arranged in an annular row around said body; and means for increasing and decreasing the working diameter of said stone holders.

2. A tool for grinding a cylindrical surface comprising a body having an inner longitudinal tube, disks mounted on opposite ends of said inner tube, an outer tube surrounding said inner tube and bearing at its opposite ends against the opposing inner sides of said disks, a head arranged at one end of said inner tube and engaging with the outer side of one of said disks, and a screw nut arranged on the opposite end of said inner tube and engaging with the outer side of the other disk, each of said disks being provided with a plurality of guide openings arranged in an annular row around the axis of said body; a plurality of supporting bars arranged around said disks; abrasive members mounted on said bars; guide rods slidable radially in said openings and connected at their outer ends with said supporting bars; and cones movable lengthwise in said inner tube'and engaging with .the inner ends of said rods.

3. A tool for grinding a cylindrical sur face comprising a body having an inner longitudinal tube, disks mounted on opposite ends of said inner tube, an outer tube surrounding said inner tube and hearing at its opposite ends against the opposing inner sides of" said disks, a head arranged at one end of said inner tube and engaging with the outer side of one of said disks, and a screw nut arranged on the opposite end of said inner tube and engaging with the outer side of vided with a plurality of guide openings arranged in an annular row around the axis of said body; a plurality of supporting bars arranged around said disks; abrasive members mounted on said bars; bushings arranged in said openings, guide rods arranged in said openings and slidable radially in said bushings and connected at their outer ends with said supporting bars; and means ar the other disk, each of said disks being prov ranged within said inner tube and engaging with the inner ends of said rods for moving the same radially.

4. An apparatus for grinding the bore of gun barrels comprising a frame having longitudinal guide ways, means for detachably connecting the frame withsaid gun barrel, a carriage movable lengthwise on the guide ways of said frame, a tool adapted to operate on the bore of -said gun barrel, means mounted on said carriage for rotating and reciprocating the same, and means for moving said carriage lengthwise on said guide ways, including a longitudinal screw shaft journaled on said frame but held against longitudinal movement, thrust eyes arranged on the carriage and embracing said shaftand spaced apart from each other, a split screw nut having sections engaging with op:

posite sides of the thread of said screw shaft between said thrust eyes, means for connecting the sections of said split nut; and means for operatively connecting said screw nut with said c'arriag'e.

5. An apparatus for grinding the bore of gun barrels comprising a frame having longitudinal guide ways, means for detachably connecting the frame with said gun barrel, a carriage movable lengthwise on the guide ways of said frame, a tool adapted to operate on the bore of said gun barrel, means mounted on said carriage for rotating and reciproeating the same, and means for moving said carriage lengthwise on said guide ways, 1n-

eluding a longitudinal screw shaft ournaled on said frame but held against longitudinal movement, thrust eyes arranged on the carrings and embracing said shaft and spaced apart from each other, a split screw nut having sections engaging with opposite sides of the thread of said screw shaft between said thrust eyes, means for connecting the sections of said split nut; and means for operatively connecting said screw nut with said carriage, consisting of a key secured between the sections of said screw nut and provided with a pin engaging with said carriage.

6 An apparatus for grinding the bore of gun barrels comprising a grinding tool adapted to operate on the bore of the gun barrel, a frame, means for actuating said tool mounted on said frame, and means for detachably connecting said. frame with the gun barrel. including a split clamping sleeve having sections embracing said gun barrel and connected with said frame, and means for connecting clamping sleeve sections and securing the same against opposite sides of the gun barrel.

7, an apparatus for grinding the bore of un barrels comprising grinding tool adaptto operate on the pore of the gun barrel, Jame, means for actuating said tool mount 1 on said frame, and means for detachably onnecting said frame with the gun barrel ncluding a split clamping sleeve having e ii-cyli rical sections provided on their er sides with adapted to engage with opposite sides of the gun barrel, means for necting said clamping sections with said me, and bolts connecting adjacent ends of said cla ning sleeve with each other. I .;;n apparatus for grinding the bore "J rrels comprising a grinding tool j tcrate on the bore of the gun barrel, s for actuating said tool mountme, and means for detachably i e with the gun b l vng slec *e having secun barrel and connectid provided with bearnith t e front end of n re 2 vas enu.

gun oarrel, and means for on eeting elampi' sleeve sections and sec" i the same against opposite sides of the 9 An apparatus for grinding a cylindrical s ace comprising a grinding to l having bi U and abrasive members mounted on sai body, a driving head, a driving shaft interposed between said and body and composed of a plurality of sections arranged end end, means for detachably connecting the opposing ends of said shaft sections including flanges secured to said ends, screws connectsaid flanges, and dowels passing through said flanges.

10. An apparatus for grinding a cylindrical surface comprising a grinding tool having a body and abrasive members mounted on said body, a driving head, a driving shaft interposed between said head and body and composed of a plurality of sections arranged end to end, means for detachably connecting the opposing ends of said shaft sections, a bushing secured to the outer end of the rearmost shaft sections, a universal joint connecting said bushing and driving head, a flange arranged on the outer end of the foremost shaft section, a universal joint connecting said flange with said tool body.

11. An apparatus for grinding a cylindrical surface con'iprising a grinding tO'll having a body and abrasive members mounted on said body, a driving head, a driving shaft interposed between said head and body and composed of a plurality of sections arranged end to end, coupling means for detachahlv connecting the opposing ends of said shaft sections including flanges mounted on said ends and fastenings connecting the opposing flanges on said sections, the peripheral portions of said flanges being constructed to form an annular groove between them, and a pilot or guide disk having a hub seated in the groove between said flanges and adapted to engage its periphery with said cylindrical surface.

12. An apparatus for grinding a cylindri cal surface comprising a grinding tool having a body, and abrasive members mounted on said body, a driving head, a driving shaft. interposed between said head and body, and composed of a plurality of sections arranged end to end, coupling means for detachablv connecting the opposing ends ofsaid shaft sections including flanges mounted on said ends and fastenings connecting the opposing flanges on said sections, the peripheral portions of said flanges being constructed to form an annular groove between them, and a pilot or guide disk having a hub seated in the groove between said flanges and ad aptcd to he gripped between said flanges so as to turn with said shaft and adapted to engage its periphery withsaid cyl ndrical surface.

13. An apparatus for grinding a cylindrical surface comprising a tooladaptcd to engagethe surface to be ground, a driving head, means for transmitting motion from said driving head to said tool including a driving shaft composed of a plurality of tubular sections arranged end to end, and

means for detachably connecting opposing Ill) ing a dowel extending into the socket of the sleeve of the first mentioned shaft section.

14. An apparatus for grinding a cylindrical surface comprising a grinding tool having abrading elements adapted to engage the surface to be ground, a driving head, a sectional shaft connecting said head and tool,

' and means for enlarging and contracting the working diameter of said tool including a sectional adjusting shaft arranged within the driving shaft and laterally movable elements which actuate said abrading elements.

15. An apparatus for grinding a cylin-" driving head, a sectional shaft connecting said head and tool, and means for enlarging and contracting the working diameter of said tool, including an adjusting shaft composed of a plurality of sections which are detachably connected with each otherand each of which is arranged in one of'said driving shaft sections and is of substantially the same length.-

17. An apparatus for grinding a cylindrical surface comprising a grinding tool adapted to engage the surface to be ground, a driving head, a sectional shaft connecting said head and tool, and means for enlarging and contracting the working diameter of said tool, including an adjusting shaft composed of a plurality of sections which are detachably connected with each other and each of which is arranged in one of said driving shaft sections and is of substantially the same length, and. bearings which are arranged in each driving shaft sectionand in which the companion adjusting shaft section is journaled.

18. An apparatus for grinding a cylindrical surface comprising a grinding tool adapted to engage the surface to be ground, a driving head, a sectional shaft connecting said 1 head and tool, and means for enlarging and contracting the Working diameter of said tool, including an adjusting shaft composed of a plurality of sections which are detachably connected with each other and each of which is arranged in one of said driving shaft sections and is of substantially the same length, bearings which are arranged in each driving shaft section and in which the companion adjusting shaft section is journaled, and means for coupling the adjacent endsof the adjusting shaft sections.

19. An apparatus for grinding a cylindrical surface comprising a grinding tool adapted to engage the surface to be ground, a driving head, a sectional shaft connecting said headand tool, and means for enlarging and contracting the working diameter of said tool, including an adjusting shaft composed of a plurality of sections which are detachably connected with each other and each of which is arranged in one of said driving shaft sections and is of substantially the same length, bearings which are arranged in each driving shaft section and in which the companion adjusting shaft section is j ournaled, and means for coupling the adjacent ends of the adjusting shaft sections, comprising a member arranged on the end of one adjust-ing shaft section and having a groove and a member arranged on the opposlng adjusting shaft sectlOIl and having a tongue engaging said groove.

. 20. An apparatus for grinding a cylindrical surface comprising a grinding tool adapted to engage the surface to be ground, a driving head, means for transmitting motion from said head to said tool including a driving shaft having a plurality of tubular sections arranged end to end and provided in their ends wlth internal outwardly facing shoulders, means for detachably connecting the opposing ends of said driving shaft sections, bearing disks arranged in said shaft sections and secured against said shoulders; and

means for expanding and contracting the working diameter of said tool including an ad usting shaft having a plurality of sections each of which is journalcd in the bearing disks of one of the driving shaft sections, the

opposing-ends of adjacent driving shaft sectionsbeing provided with cooperating pairs of plugs, one member of each pair of plugs having a flat side socket or groove and the other member of said pair having a flat side tongue or tenon engaging with said socket or groove.

21. An apparatus for grinding a cylindrical surface comprising a grinding tool 'having a body and a plurality of stones guided for radial movement on said body and adapted toengage said surface, a driving head,

means for rotating said tool by motion derived from said head including a driving shaft composed of a plurality of sections which are detachably connected with each other, and universal joints connecting opposite ends of said driving shaft with said driving head and tool body, and means for adjusting the workingdiameter of said tool including shifting means on said body for e zpanding and contracting said stones, an adjusting spindle journalcd in said driving head, an adjusting shaft having a plurality of sections journalcd in the sections of said driving between said driving shat't shaft, and universal joints connecting opposite ends of said adjusting shaft with said adjusting spindle and said shitting means and arranged adjacent to the universal joints and said driving head and tool body.

An apparatus for grinding a cylindrical surtace con'iprising a grinding tool adapted to engage the surface to be ground, a driving head, a sectional shaft connecting said head and tool means for enlargim and conti-acting the Working diameter oi said tool, including a sectional adjusting shaft arranged within the driving shaft, and a stop device for limiting the adjusting movement of said adjusting shaft.

2". An apparatus for grinding cylindrical surface comprising a grinding tool adapted to engage the surface to be ground, a driva sectional sliatt connecting said no tOOi, means for enlarging and conthe Working diameter of said tool sectional fjusting shaft ar- Within the driving shaft, and a stop ClQ'ZlCQ for limiting the adjusting movement of said adjusting shaft, including a stop men: on the driving heach an adjusting sleeve rotatably mounted on the driving ill he" I, stop ring capable of cireumtferentiai ad cment on said ad usti g sleeve and prodi a stop adapte T. engage with the ston on said driving head and gearing opconnecting said adjusting sleeve r adjusting shaft.

apparatus for grinding a cylindrice comprising a tool having a body ones mounted for radial movement on so i toward and from the surface to be opei tively to automatically and surface when engagement with said body and Lie stones become and the driving re re movement, and means for releasing said stones from said surface which are responsive to the differential position of the opposite ends of said driving shaft due to the torque in the same when twisted.

26. An apparatus for grinding a cylindrical surface comprising a grinding tool having a rotatable body, aplurality of stones capable of radial movement on said body toward and from the surface to be ground, a driving member, a driving shaft connecting said driving member with said body and adapted to be twisted when the stones become stuelr against said surface and the driving member continues its forward rotary I nnwement cam means on said body for moving said stones toward the surface to be ground and means Which'operate to Withdraw said cam means from acting on said stones when the .latter become stuck against the surface being ground and wiiich are actuated by motion of the driving end of said wait in advance the driven. end connected witn. the tool body.

i apparatus for grin arylindricai snriace comprising a e00}. naving rotatable body a plurality of stones guided on said body radial movement toward and from the surface to be ground and means niounte on said body for ex: contraca g the working oia stones including cones movable ien said body and operatii'ig on 3 driving it ember, a driving sh -"it Whicn eon: nects sai d i "i member 1 said body g or torque e being ground and the rear or advances independnd of the same and ;ree tn selves :rroni the surtace bci ien stuc arranged vv member on said said acti in driving shaft. testimony whereof I JTTO 7,. a I L- a 2 scones oecom; much against r permitting the stones to 

